1. Field of the Invention
This invention relates to an electric connection structure for electrically connecting electric parts and a flexible wiring plate disposed at a body casing side to which the electric parts are mounted, wherein the electric parts include a bobbin having coils wound therearound and a magnet rotatably supported within the bobbin.
2. Background
Conventionally, a cross coil type meter used as a speed meter or a tachometer for an automobile, for example, has been provided as one kind of each electric parts. FIG. 8 shows the configuration of the cross coil type meter in which an inner mechanism 1 is mounted on a meter casing 3. FIG. 9 shows a perspective view of the inner mechanism 1. A flexible wiring plate 4 is mounted on the lower surface of the meter casing 3 so that a driving signal inputted through the flexible wiring plate 4 is supplied to the inner mechanism 1 to thereby operate the inner mechanism 1.
In the inner mechanism 1, a pair of coils 7, 9 are wound around a bobbin 5 so as to cross to each other. A magnet 13 fixed to a pointer shaft 11 is rotatably housed within the bobbin 5. A pointer 15 is attached to a tip end (top end) of the pointer shaft 11. The pointer 15 rotates with the rotation of the magnet 13 which rotates by an angle corresponding to a difference between magnetic flux generated by the coil 7 and that generated by the coil 9 to thereby points a scale on a dial plate 17.
The bobbin 5 having the coils 7, 9 wound therearound is housed within and fixed to an electro-magnetic shield casing 19 whose upper portion is opened. The dial plate 17 is fixed through screws etc. to a pair of boss portions 5a which are provided at the right and left sides of the bobbin 5 and protrude from the upper portion of the electro-magnetic shielding casing 19. A pair of terminal fixing portions 5b protrude downward from the pair of boss portions 5a and are positioned at the opposite sides of the electro-magnetic shielding casing 19, respectively. Two pin terminals 21 are attached to each of the terminal fixing portions in a manner that these pin terminals protrude downward therefrom. That is, the two pin terminals 21 are provided at each of the left and right terminal fixing portions and hence four pin terminal portions are provided in total. Four terminals of the two coils 7 and 9 are connected to the end portions of the four pin terminals 21 at the terminal fixing portion 5b sides, respectively.
Four through holes 23 are formed in the meter casing 3 in correspondence with the four pin terminals 21, respectively. Each of the pin terminals 21 is inserted into a corresponding one of the through holes 23, and further each of contact members 25 is inserted into a corresponding one of the through holes from the flexible wiring plate 4 side and fixed thereto so as to perform electrical conduction between the pin terminals and the flexible wiring plate. The contact members 25 are inserted into the through holes 23 from the lower side in the drawing such that the contact members catch conduct portions 27 connected to a wiring pattern of the flexible wiring plate 4 into the through holes, so that the conduct portions 27 are sandwiched between the inner walls of the through holes 23 and the contact members 25. Each of the contact members 25 is provided with contact portions 25a protruding to the conducting portion 27 sides and is also provided with engagement pawls 25b for preventing the contact member from getting out of the through hole 23 downward.
When the pin terminals 21 are inserted into the contact portions 25 of the body casing 3 side, the inner mechanism 1 thus configured can be electrically connected to the flexible wiring plate 4 and mechanically fixed to the body casing 3. The dial plate 17 to which the upper side of the inner mechanism 1 is fixed to the body casing 3 through screws etc.
According to the aforesaid conventional electric connection structure, there is provided some play or tolerance between each of the pin terminals 21 of the inner mechanism 1 and the associated one of the contact members 25 of the body casing 3 sides by taking into consideration that there are some positional deviations between each of the pin terminals 21 and the associated one of the contact members 25. However, the aforesaid conventional electric connection structure has problems that the inserting procedure of the pin terminals 21 is troublesome since the number of the pin terminals to be inserted is four, and that, upon performing the inserting procedure under a condition that the dial plate 17 is mounted to the inner mechanism 1, the efficiency of the inserting procedure is quite low since it is difficult to see the insertion portion directly and hence the pin terminals are difficult to position with respect to the contact portions.
The pin terminals 21 are electrically connected with the conducting portion 27 of the flexible wiring plate 4 not directly but through the contact members 25, so that there arises a problem that the reliability of the electrical connection therebetween is not sufficient. Further, since the four contact members 25 are required and these four contact members 25 are required to be inserted into the through holes 23 of the body casing 3, there arises a problem that the number of the parts are increased and so the assembling workability is degraded and the cost of the meter is increased.